The veteran star, known as the King of Nigerian juju music, was scheduled to kick off his trek next month (Jul15), but the ongoing visa delay has left him with no choice but to pull the gigs, including a set at Chicago, Illinois' Square Roots Festival.

Alisa Baum, from the Old Town School of Folk Music, the main sponsor of the event, says, "We are beyond disappointed that King Sunny Ade has been forced to cancel his entire tour.

"As a passionate fan of African music, I was very excited about this show, which promised to be spectacular with over 20 musicians and dancers onstage.

"The recent problems that the U.S. has had processing visas has had worldwide repercussions that are quite serious. In the grand scheme of things, this cancellation doesn’t have a huge impact, but it is still a major loss for our festival."

King Sunny Ade isn't the first high-profile musician to fall victim to the State Department problem, which has yet to be fixed - last week (ends19Jun15), Australian pop stars The Veronicas also had to cancel their U.S. tour after members of their band were affected by the computer malfunction.